HIF-1α directly regulates the expression of miR-212 in pancreatic ductal adenocarcinoma by binding to the HRE at the miR-212 gene promoter. (A) Chromatin immunoprecipitation analysis identified HIF-1α binding to the miR-212 promoter (HRE, −481 bp) in the MiaPaca2 cell line in normoxic and hypoxic conditions. Luciferase analysis demonstrated that HIF-1α overexpression increased miR-212 promoter activity (containing HRE, −481 bp) in (B) MiaPaca2 and (C) 293 cell lines. **P<0.01. miR, microRNA; HIF-1α, hypoxia-inducible factor-1α; HRE, hypoxia response element; EV, empty vector; NC, negative control; PC, positive control; N, normoxia, H, hypoxia; mut, mutant.